Chemistry

Chemical Changes

Transformations that alter a substance's composition, resulting in new substances.

Clues for Chemical Changes

Indicators include color change, temperature change, gas production, formation of a precipitate, or light emission.

Physical Changes

Changes in physical properties of a substance without affecting its chemical composition.

Tests for Oxygen

Glowing splint test - a glowing splint reignites in oxygen.

Tests for Carbon Dioxide

Limewater test - bubbling CO2 through limewater turns it milky.

Tests for Hydrogen

Pop test - a lit match pops when placed in a test tube with hydrogen.

Alkali Metals

Group 1 elements on the periodic table.

Alkaline Earth Metals

Group 2 elements on the periodic table.

Transition Metals

Elements found in Groups 3-12 of the periodic table.

Halogens

Group 17 elements on the periodic table.

Noble Gases

Group 18 elements on the periodic table.

Diatomic Molecules

Molecules composed of two atoms, which may be of the same or different chemical elements.

List of Diatomic Molecules

H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂.

Ion

An atom or molecule with a net electrical charge due to loss or gain of electrons.

Ionic Charges for Group 1

+1 charge.

Ionic Charges for Group 2

+2 charge.

Ionic Charges for Group 13

+3 charge.

Ionic Charges for Group 15

-3 charge.

Ionic Charges for Group 16

-2 charge.

Ionic Charges for Group 17

-1 charge.

Ionic Compounds

Formed from the electrostatic attraction between oppositely charged ions.

Molecular Compounds

Formed by covalent bonds between atoms.

Polyatomic Ions

Ions composed of two or more atoms that carry a charge.

Oxyacids

Acids containing oxygen, formed from the reaction of water with a nonmetal oxide.

Law of Conservation of Mass

Mass is neither created nor destroyed in a chemical reaction.

Mass Calculation for Reactions

Mass of D = (mass of A + mass of B) - mass of C.

Chemical Equations

Uses chemical formulas to represent reactants and products.

Balanced Equations

Equal number of atoms of each element on both sides.

Types of Chemical Reactions

Includes synthesis, decomposition, single diplacement, double diplacement, and combustion.

Properties of Acids

Sour taste, pH is lower than 7, react with metals to produce hydrogen gas, turn blue litmus red.

Properties of Bases

Bitter taste, slippery feel, pH higher than 7, turn red litmus blue.

pH Scale

Ranges from 0 to 14; acids < 7, neutral at 7, bases > 7.

Neutralization Reaction

A reaction between an acid and a base producing water and a salt.

Synthesis reaction

A + B = AB

Decomposition reaction

AB = A + B

Single displacement reaction

A + BC = B + AC

Double displacement reaction

AB + CD = AD + CB

Complete combustion

Involves the burning of a substance with oxygen to produce oxides and energy

Incomplete combustion

When hydrocarbons are not burned completely

Complete combustion reaction

CxHy + O2 = CO2 + H2O + energy

Incomplete combustion reactions

CxHy + O2 = CO2 + H2O + CO + C + energy